mini-roundaboutnoun [ C ]
uk/ˌmɪn.iˈraʊnd.ə.baʊt//ˌmɪn.iˈraʊnd.ə.baʊt/UKa small, flat roundabout (= a place where three or more roads join and traffic must go around a circular area in the middle, rather than straight across) that is shown only by marks on the road, and that it is possible to drive over if necessary:
At a mini-roundabout it is important to remember that all vehicles must pass round the central markings, unless they are too large to do so.